Explaining encrypted messaging: What on earth is meta-data? 

Published 2016-09-28 on flowinho.io

category | knowledge privacy encryption messenger security metadata

With Whatsapp now sending meta-data to facebook a lot of family-members started to ask me: whats this all about?
So i decided to come up with a series about encrypted messaging.

This is part two of a three articles spanning series trying to explain encrypted messaging to less technologically knowledgeable people. Part two: explaining meta-data, why parts of it cannot be avoided and why it’s important.

Communication is more than just the content being exchanged

Communication can be found at the root of almost everything, because communication is meant for the exchange of information. Almost all living beings communicate with each other, some in a more complex, some in a more basic way.

In general, communication is used to exchange information. Bees dance to tell their bee-hive where they found those big yellow flowers, rabbits warn each other of potential enemies by stomping on the ground, humans talk to each other about really, really important things like “Wow, that starbucks guy just wrote your name wrong, that’s hilarious”. Kudos to my cousin for this.

But this part of Encrypted messaging is not about the content of communications, it’s about what happens around the individuals that exchange information and what is needed to make communication happen.

A classic face-to-face dialogue

Imagine yourself walking through the streets, when you take a turn around the corner and suddenly meet one of your best friends. You greet him and ask him how he’s doing, but he’s not up for a talk since his dog has a serious injury and she (the dog is named Sheila) needs to see the vet right away. So you continue your walk.

Not much information here, huh? I mean, yeah, his dog has an injury, but nothing else. But the information is stored in the scenario that made you meet your friend.

From an outside point-of-view, there are several things that could be seen:

  • You where at that very location, your friend was there as well.
  • He had his dog with him.
  • You are close to each other, since you greeted him very enthusiastically.
  • You talked about something sad that drastically changed your mood.
  • Its obviously related to the dog since you both kept watching at her while you were talking.
  • You wore white shoes, blue jeans, a yellow-striped polo-shirt, and a basecap.
  • He wore similar jeans, leather shoes and a Lacosy shirt.
  • You both weren’t at work since you obviously met in the streets.
  • He most likely had to take a day off to take his dog to the vet.

The question is? Could the transmission of this data have been avoided?

Not really.

There are several necessary requirements for a face-to-face dialogue. For example, you have to be at the same location as the person you are talking to, at the very same time. The other person has to listen to you. You have to speak the same language or at least be able to understand the language the other person is talking.

So if a communication like that occurs, some data is generated by necesarity. This information is called meta-data, in this context. It’s the data that is listed above.


Let’s take a look on how the generation of meta-data has changed over the years. Phone calls have been a shining example of meta-data processing for years.

What can we tell about a woman phoning a man?

I’ll use an example to demonstrate this.

In the year 1920

It’s Thursday morning. A woman living in the outskirts of London phones her doctor, a well-known and empathic doctor specialized in women’s needs. They talk for roughly 18 minutes, then she hangs up and leaves the house.

We witness her leaving the house and decide to follow her because she seems nervous. She takes a cap and rides to the doctors address. At the doctor’s, she quickly enters the house and stays there for about 2-3 hours, before leaving the house, slightly irritated.

After yet another cab-ride she’s back at home.

What do you think happened to the woman? Why did she go see the doctor?

What meta-data can you gather from this happenings? Did she betray her husband? Is she even married? Does she have feelings for the doctor? Maybe she suffers some kind of disease?

Let’s enjoy this story again, this time by having a look at the same scenario 96 years later. Maybe we find an answer to this questions.

In the year 2016

It’s Thursday morning, the day before black friday. A woman whose Facebook profile indicates she is married to a sailor and lives in 10th-Glemoraing-Street, 123456 London phones her doctor using her Nexus 5 after liking the vacational pictures of her - according to Facebook - 3 years older sister, who lives in (… you get the idea…).

Her name is Sue Anderson, because thats the name that matches her phone number in the WhatsApp database. The doctor is a tall, white haired, well-known and empathic doctor that posted on LinkedIn that he visited three different Universities where he studied various medicinal topics. He is specialized in women’s needs. He lives in 12-Glemoraing-Street, 123456 London. They talk for roughly 18minutes, then she hangs up and leaves the house.

We witness her leaving the house and decide to follow her because she seems nervous. She takes a cap and rides to the doctors address. During the 8 minutes cab ride she messages her best friend for about 3-4 minutes and then posts “OMG im so excited - i feel so happy” on Facebook — 27 people like this, including her best friend, her sister, her mother, her husband and several of her working colleagues.

At the doctor’s, she quickly enters the house and stays there for about 2-3 hours, before leaving the house, slightly irritated.

After yet another cab-ride she’s back at home. She starts browsing Amazon for baby-clothing while calling her mother.

Let’s take a quick break.

Phew, that was a lot of information, a lot of meta-data, right?

I’m sorry to irritate you, but there is actually way more. A gazillion tons of more data. But describing all of it would turn this article into something that will never be read.

So why are phone-calls a great example for meta-data processing? Phone calls have always played a huge role in e.g. criminal investigations. The problem is: wire-tapping a phone-call violates the rights of the persons participating in that call. Even when there is threat inbound, wire-tapping a call is something a judge has to agree with.

But gathering meta-data is different, because no-one is actually listening to the phone call.

The point is: every single activity in our lives is gathered and processed. We expose most of it ourselves by updating our Facebook profiles, exchange career information via LinkedIn, chat casually about our next votes on Twitter, browse specific items on Amazon, share what we just bought, … the list is endless.

A short summary

Meta-data is the information that happens around our communication. It’s the time, the location, the situation that makes communication possible, and the tools we use.

Besides the actual content, it’s the most valuable information of communication, since often the content of the communication can be guessed by looking at the meta-data.

Why all this?

This very long article was necessary to put a spotlight on something that is often overlooked or completely ignored: meta-data. When communication happens, there is a ton of information around it.

Valuable information.

Special thanks

Special thanks to my talented and awesome colleague Mesut Kaya who drew the images in the articles. Feel free to visit his Twitter-Account, iammesutkaya

Next up: Explaining encrypted messaging: The difference between messengers

This post appeared first on flowinho.com, on 9/28/2016